We propose to understand the role of oop RNA in the development of bacteriophage lambda. Studies on control of the synthesis and determination of the physiological role of oop RNA are important because the synthesis of oop is directly coupled to, and is apparently essential for, the initiation of (a) bidirection lambda replication and (b) repressor establishment transcription. In the coming year we hope to reduce our past emphasis on determining how oop is involved in repressor establishment transcription and concentrate on understanding the mechanism of initiation of lambda replication. We will specifically study: (1) the variety and nature of interaction of the phage and host proteins required for initiation of lambda replication; (2) determine how the synthesis of discontinuously replicated DNA is controlled; (3) determine if oop RNA primes DNA synthesis in vivo and in vitro; (4) determine the nature of transcriptional activation. BIBLIOGRAPHIC REFERENCES: Hayes, S. Control of lambda repressor establishment transcription. Arrowhead Genetics Conference, Lake Arrowhead, CA. January 30, 1976. Hayes, S.J. Control of repressor establishment transcription. ICN-UCLA Winter Conference: Molecular mechanisms in the control of gene expression. Keystone, CO, March 21, 1976.